Information about plants & gardens for Brisbane & Qld


Welcome to Queensland's gateway to gardening - a collection of news, information, resources and ideas of interest to gardeners, especially residents of Queensland, Australia.

Get Results Gardening 01-03-2024
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Garden Events 2024

Organising a garden show, open garden, plant workshop or similar event in Qld this year? Submit your dates for inclusion in the Queensland Gardening Events Diary now. You can send in additional details (key attractions, opening times, etc) closer to the event if you wish, but adding your date ASAP will give you more exposure to potential visitors and stallholders. Basic text listings (which can include a website link) are free. Featured listings are also available for a modest fee. Go to the Queensland Gardening Events Diary for more information or to just to see what's listed for 2024 so far.

The Garden Scene

News about plants and gardens in Queensland and around the world. Most of these items are edited versions of news that was covered in past editions of Get Results Gardening.

Aerial Roots Are Houseplant Helpers

Many popular indoor plants come from tropical forests and produce aerial roots that help them cling to and climb trees. Aerial roots might absorb water and nutrients too, but little attention has been paid to their possible absorptive role in the cultivation of such plants. However, recent research has looked at nitrogen uptake in three aroid species - Philodendron scandens, Epipremnum aureum and Anthurium andreanum. For all three, the aerial roots were actually better at absorbing nitrogen than the roots in the potting mix. "A simple spray with water and some plant food to the aerial roots may help optimise the amount of nutrients the plant gets," said lead researcher Amanda Rasmussen. "The results of this study are really exciting as they could transform the way we feed certain types of plants." It was also found that plants at the higher of the two humidity levels tested put on more growth overall. Source: New research roots out solution to keeping houseplants healthy (February 2023).

Trees Adapt to Water Availability

A research team assessed 30 tree species growing in Southern California (including some Australian natives and some familiar exotics), measuring traits associated with water use and carbon gain. They showed that the more water a reputedly "drought tolerant" tree can access, the more it will use. Such trees could be consuming more water than expected if the surrounding landscape is irrigated. This showed that the biology of trees in the wild can't necessarily be used to predict their behaviour in an urban environment. Source: Landscaping for drought: we're doing it wrong. (January 2023)

Goodbye, Tulip Trees

Fraser Coast Regional Council's African tulip tree eradication program started in December 2020 with the removal of all known trees from council land. Now the program is entering its next phase as private property owners are urged to remove their own trees. The council is aware of about 1,000 such specimens and have issued educational notices to hundreds of affected property owners. Many have subsequently removed the woody weeds. As encouragement, council is offering free native seedlings as replacements to Fraser Coast residents who send before and after photos of their tulip tree removals. Source: All African Tulip Trees in Council parks being removed (December 2022)

Fighting Rust With RNA Technology

A team at the University of Queensland and Department of Agriculture and Fisheries using RNA interference (RNAi) technology to develop a new way to fight myrtle rust (Austropuccinia psidii). A spray containing double-stranded RNA that targets essential genes in the fungus is simply applied to the plant. This paves the way for many more rust control products that are safer and more environmentally-friendly than fungicides currently available. The team have already demonstrated inhibition of frangipani rust (Coleosporium plumeriae) using RNAi. Source: Scientists tackle rusty plant threat (December 2022)

Better Work, Naturally

Research conducted at Bond University on the Gold Coast suggests that views of nature from office windows could improve workers' performance. Virtual reality (VR) was used in the study to provide a consistent and controlled experience to participants. The three views tested were an office with no window, a shuttered window, or a window view of nature. When people were able to see sky and trees, they did better in a creative task and reported better moods. Source: A view to a chill: why every office needs a window

A Pandemic-Defying Response

A UK study looking at therapeutic community gardening by people with mental health issues has demonstrated a beneficial effect, which is consistent with a variety of other research linking gardening and exposure to nature to better human health. What's notable about this particular study is that it commenced prior to the start of the Covid-19 crisis and continued through it. Even while the population in general was under increased stress, the participants reported improvement in self-reported life satisfaction and mental well-being. Although the cost-effectiveness of such interventions still needs to be proven, this does point to the potential of horticulture as a therapeutic strategy that could take pressure off other parts of a nation's health system. Source: Gardening eased lockdown loneliness as pandemic paralyzed Britain (November 2022)

Not-So-Compostable Plastics

Observations of home compost bins in the UK showed that 60% of plastics certified as "home compostable" were not fully breaking down in real-world conditions. This means the plastic will end up in the soil when the compost is used in gardens. Furthermore, confusion over the different plastic types led to inclusion of inappropriate plastics in the compost. The researchers suggest that "home compostable" plastics need to be improved. Until then, it would be better if they could be collected for industrial composting. Full report: The Big Compost Experiment: Using citizen science to assess the impact and effectiveness of biodegradable and compostable plastics in UK home composting (DOI: 10.3389/frsus.2022.942724)

Drain Gain

A new avenue of 36 Queensland blue gums along a Toogoom drain started with a suggestion from a local resident. Now the reserve will a better place for wildlife and people. The planting is part the Greening the Fraser Coast program, under which the Council has committed to plant 100,000 trees by 2030. Source: Trees beautify Toogoom drain (November 2022)

Plaque for Ipswich Jacarandas

While the NSW town of Grafton is known for its jacarandas, the City of Ipswich in Qld also has major plantings. The first ones were in Brisbane Terrace, Goodna 90 years ago, done by work gangs during the great Depression. The historical significance of these trees and their ongoing contribution to Ipswich has recently been marked with the installation of a commemorative plaque. Although jacarandas can live for 200 years and many of the oldest trees have survived 90 years and three major floods, many have have had to be removed due to storm damage and poor health. Ipswich City council undertook a replacement program in 2021, installing 50 new trees in various locations. Source: Ipswich’s 90-year-old jacarandas celebrated with historical plaque (October 2022)

Helping Boab Heritage Live Forever

In Australia's Tanami desert (which extends from the NT into WA), there are boabs that are also precious works of Indigenous art. Now researchers are working with Traditional Owners to document them before the trees succumb to old age. The actual age of the trees is uncertain, but there's no time to waste in recording the carvings on their bark. "Unlike most Australian trees, the inner wood of boabs is soft and fibrous and when the trees dies, they just collapse," said Professor Sue O’Connor of the ANU. "We hope that our research will bring the art in the bark of these remarkable trees to many more Australians so that they can be appreciated for generations to come." So far, twelve trees with carvings have been catalogued in this very remote region, but further expeditions may find more. Source: Race against time to find Indigenous carvings on boab trees (October 2022)

More Logan Oldies Located

Ongoing testing and cataloguing of significant trees in Logan City has identified more notable residents. A forest red gum (Eucalyptus tereticornis) at Jimboomba has been estimated at 359 years old. This is not far behind the 380 year-old "Gandalf", a North Maclean tallowwwod (Eucalyptus microcorys) that was scientifically dated 3 years ago. A 270 year-old thick-leaved mahogany (Eucalyptus carnea) was also found at Priestdale in the recent round of testing. Age is determined by inserting a very thin drill into the trees' trunks and using variation in resistance to detect and count the seasonal growth rings. Source: New giant of the forest (October 2022)

Tree Inequality in Brisbane

Provision of street trees in Brisbane may be related to the socio-economic level of the suburbs, suggests a preliminary study by urban planners at the University of Queensland. Of the three suburbs compared, the one with the lowest average income (Deagon) had the lowest number per kilometre of street (77). However, the middle income Riverhills (113) had more trees than the high-income Parkinson (87). This was a pilot study and more extensive data between and within suburbs may reveal more definitive associations with income, street design and street usage. The researchers are particularly concerned with the relationship between shady trees, pedestrians and public transport uptake. Source: Tree study shows low-income Brisbane suburbs need more shade (September 2022)

Peat Ban to Hit UK Gardeners

The phasing out of peat in potting mixes has taken a significant step forward with the British government announcing that peat use by amateur gardeners will be banned by 2024. While this doesn't affect Australian gardeners directly, we might expect it to increase demand for coir, making this and other internationally-sourced peat substitutes more expensive for us to obtain. On the upside, it may lend further impetus into research and development of other potting mix ingredients that might result in even better potting mixes for all of us. In the meantime, it will be interesting to see how UK gardeners rate the wood and bark based mixes we've been using for years compared to the traditional peat-based ones. (September 2022)

Tredge Against Pollution

A screen of vegetation might seem like a good way to reduce traffic pollution from the road reaching your home, but could it really work? A study in the United Kingdom has shown that "tredges" (trees managed as head-high hedges) lowered the amount of particulates reaching playgrounds. However, the species composition did make a difference to their effectiveness. Of the three tredge types compared in this study, western red cedar (Thuja plicata) performed best. The fine, roughly textured foliage of this conifer was good at capturing particulates. On the other hand, the smooth, waxy leaves of ivy can block polluted air somewhat, but aren't very good at capturing particulates. While research into species suitable for Australian climates is obviously necessary, it does appear that the right vegetation could make a meaningful difference in urban areas. Source: New evidence shows planting around school playgrounds protects children from air pollution (August 2022)

Chat Botany

The American online nursery did a survey and found that 48% of respondents talk to their indoor and/or outdoor plants. Many of those people think it helps plants grow and also helps their own mental health. Some think of their plants as pets and even hug and kiss them. Source: Nearly 50% of People Talk to Their Plants and Trees, (September 2022)

High Hedge Warning

Crimestoppers in the United Kingdom are warning homeowners that hedge height can affect the risk of burglaries. They're recommending that front hedges be no more than 1m high and that rear hedges be 1.8m high or higher. A poll of UK households commissioned by John Lewis Home Insurance indicated a lack of awareness about this issue and what height hedges should be to improve security. "Those surveyed said they keep their front hedge high to prevent people ... seeing in but we know that what matters most to criminals is not being seen," said Mick Duthie from Crimestoppers. "A high front hedge gives them cover while they’re in a property or garden, and a low rear hedge gives them easy access to escape out the back." Source: Warning high hedges increase burglary risk (July 2022)

Snail Pellets Implicated in Bowerbird Deaths

Blue snail pellets are suspected of causing several regent bowerbird deaths in the Mount Tamborine region. The Queensland Parks and Wildlife Service is requesting that residents stop using the pellets immediately. During the breeding season (August to January), males like to decorate their bowers with blue objects to attract a female. Deceased birds of both sexes have been discovered. Investigations are ongoing. Anyone with information about these deaths or noticing unusual deaths of any bird species in Queensland should report them to the QPWS on 1300 130 372. Source: Bowerbird deaths linked to poison (August 2022)

Many Suburban Birds in Decline

Many native bird species that were previously considered "common" in Australian cities and suburbs are becoming less so, according to data collected by citizen scientists in the greater Brisbane, Sydney, Melbourne and Perth regions. Analysis supports the view that smaller-sized birds tend to be less competitive in urban environments, but galah and kookaburra numbers are dropping too. However, there have been increases in noisy miners and rainbow lorikeets. "Planting more diverse forms of natives vegetation, particularly less nectar-rich species like wattles and she-oaks, can help maintain a diverse ecosystem," said researcher Carly Campbell. Source: Decreasing backyard bird diversity flies under the radar (August 2022)

Coastal Cravings

Home design website Houzz Australia has released its 2022 Emerging Home Design Trends Report. The trends highlighted have been identified from the website's own search data, comparing the January-March period this year with the same period last year. As far as landscapes are concerned, it seems that the trend for resort-style, outdoor living is marching on, with increasing interest in Hamptons/coastal and Palm Springs styles. Interest in Australian native gardens is also on the rise. Get the report here: 2022 Houzz Australia Emerging Home Design Trends Report at (August 2022)

Looks Matter

Research has indicated that houseplants can improve our lives, but the results vary across across different studies. Could the type of plant be important? UK researchers asked that question and found that people responded best to lush plants with a dense, rounded canopy of leaves. Spiky or spreading plants were less appealing. The 12 images of assorted plants presented to participants included 4 Ficus benjamina shaped in different ways. Within that one species there was a preference for the one with the full, spherical top. A healthy palm performed well, perhaps because of a positive association with holidays abroad. However, an obviously unhealthy palm sparked negative responses, highlighting that a plant's ability to thrive under available conditions is the most important thing of all. Source: Rounded, leafy houseplants give the biggest boost to well-being, new research reveals, Royal Horticultural Society. (2022) Full Study: The appearance of indoor plants and their effect on people's perceptions of indoor air quality and subjective well-being, Building and Environment

Noosa Heads Tree Deaths

Testing of soil near dead trees at Noosa Heads has shown the presence of two herbicides often used to kill trees on grazing lands. Noosa Council will be working with Settler’s Cove to restore the area. Remediation of the soil to remove the herbicide is planned. The dead trees, which include Bribie Island Pines and Hard Quandongs, will be left in place and native vines planted to climb up them. New trees will also be planted and nesting boxes installed to support wildlife. Source: Remediation work underway after suspected Noosa Heads tree kill (August 2022)

Is Your Gold Coast Street Neat?

The City of Gold Coast's My Neat Street initiative is allowing residents to nominate streets of "exceptional upkeep". Great streets will be recognised on the 2022 My Neat Street Honour Roll to be announced in December. Nominators who submit an eligible nomination will go into a prize draw. "If your street goes that extra mile when it comes to garden maintenance, clearing your gutters or any other neat work that should be recognised, we want to hear from you," said Councillor Hermann Vorster. "It’s also your chance to engage with your neighbours, report any concerns to the City or relevant authority and build a connected community." Nominations close 30th September, 2022. There's more information at the City of Gold Coast website: My Neat Street. (July 2022)

Macadamia Frozen in Time

All four native species of Macadamia are now threatened in what remains of their Australia rainforest habitats. Conserving them isn't just important for environmental reasons - plants from the wild could hold useful genes for the improvement of commercial nut crops in the future. Unfortunately, its difficult to preserve this genetic resource using conventional long-term storage methods, due to the size and high oil content of the seeds. The Australian Institute of Botanical Science and the University of Queensland are now working together to develop new methods to preserve these important species. One possibility is removal of the tiny embryo from the seed and storing it in liquid nitrogen. They will also try cryopreserving shoot tips grown in tissue culture. Source: Macadamia conservation a tough nut to crack (July 2022)

UQ a Part of RNA Revolution

Akin to vaccines for plants, RNA treatments have the potential to fight many different pests and diseases. A hurdle is delivery to appropriate sites within plant tissues. However, the University of Queensland has been developing a carrier technology they call BioClay™, which could help unlock the potential of double-stranded RNA (dsRNA) to provide safe and efficient plant protection. Whitefly is very troublesome because it not only sucks the sap of plants, but can also transmit viruses. What's more, it's difficult to control. However, the effectiveness of an RNA/BioClay spray against silverleaf whitefly has now been demonstrated, which UQ is hailing as a breakthrough. The whiteflies ingest the dsRNA, which attacks vital genes in the insects. By targeting genes specific to silverleaf whitefly, beneficial insects are not harmed. The next step towards making this a commercial product will be on-farm testing with industry partner Nufarm. Source: UQ research to revolutionise pest control around the world (May 2022)

That's Cool, Eudlo

Following extensive community consultation, the Sunshine Coast hinterland town of Eudlo has been given a green boost with a makeover of the town's main thoroughfare. As well as an upgraded pedestrian crossing, Rosebud Street now has three new garden beds containing large shade trees and over 700 shrubs and groundcovers. Solar-powered lights are on the way. Source: Fresh and shady upgrade for Eudlo's main street, Sunshine Coast Regional Council (April 2022)

Saving Energy Needs People Power

A 30% decline in residential trees over the past decade is making Australian suburbs hotter, according to researchers at the University of South Australia. The UniSA team have recently developed a strategy to help planners and developers. However, a shift in attitudes by residents themselves will also be required. Source: Neighbourhoods feeling the heat as medium density housing robs suburbs of street and garden trees (March, 2022)

Maybe Houseplants Can Help After All

Following a NASA study in the late 1980s, plants have been widely touted as means of reducing indoor air pollution even though subsequent research did not support this conclusion. Realistically, a few plants were considered unlikely to make an appreciable difference in a normal home or office. However, those studies focussed on volatile organic compounds (VOCs). New research out the UK has indicated that potted plants could reduce levels of a different pollutant - nitrogen dioxide (NO2). This gas results from burning wood or fossil fuels. Indoor levels can be raised by heavy traffic outside. As yet, the mechanism on NO2 absorption is unknown, but could involve the soil. Three quite different species of plants were tested, but were similarly effective. Interestingly, microbes in the potting mix rather than the plants were thought to be largely responsible for VOC reduction in the NASA study, too. Source: Common houseplants can improve air quality indoors (March, 2022)

Bats Getting the Message

Sprinklers are being installed In Sunshine Coast trees - not for irrigation, but to deter flying foxes. Porter Park at Golden Beach is the latest neighbourhood to benefit from this management approach after proving successful in several other locations. Emitters are located in treetops on edges of the park with houses nearby. The noise and motion created by the water alarms the animals, making the centre of the park a more attractive option for them. The sprinklers are timed to come on at intervals thorough the day, but residents will be able to trigger the system, too. Source: Sprinklers provide a different type of relief for Golden Beach residents (February 2022)

Orchid House Welcomes More Visitors

Expansion of the The Orchid House at the Hervey Bay Botanic Gardens has been proclaimed a great success, with visitor numbers growing to over 15,000 people in 2021. The facility was doubled in size in 2019 and additional improvements made in 2021. Source: Visitor numbers on the rise at the Orchid House (February 2022)

Courting Coolness

A study conducted in Potsdam, Germany, compared four comparable urban spaces surrounded by five-story apartments. They found that even small differences in the amount of greenery produced benefits for residents, particularly summer cooling. The presence of trees and shrubs reduced temperatures up to 11°C in these courtyards. The maximum value recorded in the least-vegetated courtyard during the study was 45°C, demonstrating that even in northern Europe, humans can be at risk of heat stress. If such events become more frequent, the need for sustainable mitigation measures becomes even more important. Source: Green backyards help increase urban climate resilience: Here is how (January 2022)

Hard Graft Now Possible

Grafting is a well established horicultural practice with many potential benefits (see Get Results Gardening 11 & 18 June). However, successful connection relies on aligning the cambium tissue, the sub-surface layer in which cell division occurs. Among flowering plants, this requirement has has limited grafting to the group known as the dicotyledons. The monocotyledons, on the other hand, have a quite different internal stem structure and it was believed they could never be grafted. However, a new technique has been invented that makes it possible using embryonic tissue. The researchers have had success with a quite diverse range of monocots including pineapple, banana, onion, tequila agave and date palm. Down the track, it may become practical to utilise grafting to introduce disease resistance or dwarfing into such important economic crops, and maybe even some ornamentals. Besides palms, a huge number of our garden plants are monocots - orchids, flowering bulbs, grasses, gingers, cordylines and philodendrons, to name a few. Source: New grafting technique could combat the disease threatening Cavendish bananas (December 2021)

Roots and Shade

When plants aren't getting enough light, growth is reduced and elongated stems "stretch" towards the light source. We don't usually think about what's happening below ground, but new research has shown that excessive shade has an effect there, too. Roots of both tomato and Arabidopsis were found to be shorter and less developed when light was reduced. This appears to be a specific response associated with the activation of stress genes and possibly involving ethylene (the fruit-ripening gas). It enables the plants to direct more of their limited resources to growth of the light-harvesting parts. In the garden, shaded areas (under eaves, around trees) are often much drier than elsewhere. The inhibition of root growth due to shade could be making it even more difficult for plants to cope than simple observation of the soil would suggest. Home gardeners might also consider how spacing their vegetables too closely might stunt the roots due to mutual shading, even if soil conditions are very good. In this study, the researchers were primarily interested in how crop plants respond to overcrowding, with a view to engineering varieties that can be efficiently produced at higher densities. Source: Why roots don’t grow in the shade (October 2021)

New Garden a Feast for Seniors' Senses

A garden especially designed for seniors has opened at Cascade Gardens in Broadbeach on the Gold Coast. Besides wheelchair-accessible garden beds, there are art objects and a giant xylophone to engage all the senses. The project was jointly funded by the City and State Governments. Dementia Australia’s Men’s Shed created several items for the garden. Source: Sensory gardens show love for our city seniors (October 2021)

Nature Helped Kids Cope

A survey of UK families indicates that children who had increased exposure to nature during the first COVID-19 lockdown exhibited fewer behavioural or emotional problems compared to those to had the same or less exposure. Their socio-economic status did not make a difference, except that children from more affluent families tended to have more access to nature during that time. That could be gardening, playing in the garden or other outdoor activities. The findings are in line with other studies linking nature and better wellbeing. These researchers suggest that supporting the connection at home and at school could be a low-cost way of improving child mental health, in or out of lockdown. Source: Lockdown wellbeing: children who spent more time in nature fared best (October 2021)

Tiny Plastic Particles a Big Worry

An Australian study has shown how plastic in the garden - whether through careless disposal of waste or deliberate use - can impact soil health and the wider environment. Soil samples were collected in the vicinity of two plastic items in an ordinary South Australian garden. One was a piece of discarded polyethylene bubble wrap. The other was polypropylene weed control fabric. Both had been in contact with the soil for seven years. Analysis showed that degradation over that time had released plastic particles into the soil. These ranged in size from visible fragments to microplastic particles a fraction of a millimetre in diameter. Although the techniques in this study were not suitable for detection of ultra-small nanoplastics, the results suggest that these would also be present. Source: Reducing plastic in gardens (October 2021)

Grass Pollen Booming in Brisbane

Grass pollen is a major cause of hay fever and allergies. The QUT Allergy Research Group has looked at airborne levels recorded at the Air Quality Monitoring Station in Rocklea, Brisbane over 1994-1999 and compared them with data from 2016-2020. In both periods, the main pollen season starts between mid-October and mid-December. However, the concentration of grass pollen in the air now gets almost three times higher, with more high-risk days. Concurrent meteorological data and satellite imagery were also analysed. Source: Allergy-causing pollen levels much higher in 2010s than 1990s (September, 2021)

Delicious Dough

Researchers might just have discovered the cheapest, safest and most effective lure for slugs and snails yet. Observation of six species across three American states showed that bread dough - simply made with flour, water and yeast - was more attractive to the pests than a commercial bait or other food lures tested, including beer. Another benefit is that the dough can keep working for days. The exact reason for bread dough's allure to slugs and snails is not known, but is probably something to do with the fermentation process. Source: Slugs and snails, destructors of crops and gardens, could be controlled by bread dough (August 2021)

Happy 100th

Planting a tree in a public park to recognise residents who reach 100 years has become a popular practice throughout the Fraser Coast region since it was introduced by the former Maryborough City Council. It seems there's something of a centenarian boom underway, which may be something to do with the baby boom following World War One. Given the level of interest in marking these birthdays with public tree planting, Fraser Coast Regional Council is considering a formal application process and eligibility criteria. Source: Have your say on Council's plan to plant trees to celebrate centenarians, Fraser Coast Regional Council (August 2021)

Respect Our Wrack

Removing beach-cast seaweed (sea wrack) to manufacture garden products or make the beaches appealing to tourists could impact sea bird populations. In "the first study of its kind," ecologists at the University of South Australia found that fresh and aged wrack of various depths had different temperature profiles, allowing shore birds to be able to take advantage of the warmest spots available at various times of the day to conserve energy. Source: Conserving coastal seaweed: a must have for migrating sea birds (June 2021)

Some older news items of continuing interest have been moved to appropriate subject pages. Check the Guide to Pages or use the search function at the top of the page. Older news about the benefits to physical or mental health and society will be collected in a new page: Effect of gardens & gardening on human health. Items related to property value are at Landscaping & property values


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